Without delay, let's solve this. We've got 309 and we will be multiplying it by 72, that is, adding 309 to itself 72 times.
Step 1: 0 + 309 = 309
Step 2: 309 + 309 = 618
Step 3: 618 + 309 = 927
Step 4: 927 + 309 = 1236
Step 5: 1236 + 309 = 1545
Step 6: 1545 + 309 = 1854
Step 7: 1854 + 309 = 2163
Step 8: 2163 + 309 = 2472
Step 9: 2472 + 309 = 2781
Step 10: 2781 + 309 = 3090
Step 11: 3090 + 309 = 3399
Step 12: 3399 + 309 = 3708
Step 13: 3708 + 309 = 4017
Step 14: 4017 + 309 = 4326
Step 15: 4326 + 309 = 4635
Step 16: 4635 + 309 = 4944
Step 17: 4944 + 309 = 5253
Step 18: 5253 + 309 = 5562
Step 19: 5562 + 309 = 5871
Step 20: 5871 + 309 = 6180
Step 21: 6180 + 309 = 6489
Step 22: 6489 + 309 = 6798
Step 23: 6798 + 309 = 7107
Step 24: 7107 + 309 = 7416
Step 25: 7416 + 309 = 7725
Step 26: 7725 + 309 = 8034
Step 27: 8034 + 309 = 8343
Step 28: 8343 + 309 = 8652
Step 29: 8652 + 309 = 8961
Step 30: 8961 + 309 = 9270
Step 31: 9270 + 309 = 9579
Step 32: 9579 + 309 = 9888
Step 33: 9888 + 309 = 10197
Step 34: 10197 + 309 = 10506
Step 35: 10506 + 309 = 10815
Step 36: 10815 + 309 = 11124
Step 37: 11124 + 309 = 11433
Step 38: 11433 + 309 = 11742
Step 39: 11742 + 309 = 12051
Step 40: 12051 + 309 = 12360
Step 41: 12360 + 309 = 12669
Step 42: 12669 + 309 = 12978
Step 43: 12978 + 309 = 13287
Step 44: 13287 + 309 = 13596
Step 45: 13596 + 309 = 13905
Step 46: 13905 + 309 = 14214
Step 47: 14214 + 309 = 14523
Step 48: 14523 + 309 = 14832
Step 49: 14832 + 309 = 15141
Step 50: 15141 + 309 = 15450
Step 51: 15450 + 309 = 15759
Step 52: 15759 + 309 = 16068
Step 53: 16068 + 309 = 16377
Step 54: 16377 + 309 = 16686
Step 55: 16686 + 309 = 16995
Step 56: 16995 + 309 = 17304
Step 57: 17304 + 309 = 17613
Step 58: 17613 + 309 = 17922
Step 59: 17922 + 309 = 18231
Step 60: 18231 + 309 = 18540
Step 61: 18540 + 309 = 18849
Step 62: 18849 + 309 = 19158
Step 63: 19158 + 309 = 19467
Step 64: 19467 + 309 = 19776
Step 65: 19776 + 309 = 20085
Step 66: 20085 + 309 = 20394
Step 67: 20394 + 309 = 20703
Step 68: 20703 + 309 = 21012
Step 69: 21012 + 309 = 21321
Step 70: 21321 + 309 = 21630
Step 71: 21630 + 309 = 21939
Step 72: 21939 + 309 = 22248

So, 309*72 = 22248